1 /* |
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2 * pixel format descriptor |
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3 * Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at> |
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4 * |
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5 * This file is part of Libav. |
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6 * |
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7 * Libav is free software; you can redistribute it and/or |
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8 * modify it under the terms of the GNU Lesser General Public |
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9 * License as published by the Free Software Foundation; either |
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10 * version 2.1 of the License, or (at your option) any later version. |
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11 * |
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12 * Libav is distributed in the hope that it will be useful, |
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13 * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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15 * Lesser General Public License for more details. |
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16 * |
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17 * You should have received a copy of the GNU Lesser General Public |
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18 * License along with Libav; if not, write to the Free Software |
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19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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20 */ |
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21 |
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22 #ifndef AVUTIL_PIXDESC_H |
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23 #define AVUTIL_PIXDESC_H |
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24 |
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25 #include <inttypes.h> |
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26 #include "pixfmt.h" |
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27 |
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28 typedef struct AVComponentDescriptor{ |
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29 uint16_t plane :2; ///< which of the 4 planes contains the component |
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30 |
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31 /** |
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32 * Number of elements between 2 horizontally consecutive pixels minus 1. |
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33 * Elements are bits for bitstream formats, bytes otherwise. |
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34 */ |
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35 uint16_t step_minus1 :3; |
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36 |
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37 /** |
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38 * Number of elements before the component of the first pixel plus 1. |
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39 * Elements are bits for bitstream formats, bytes otherwise. |
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40 */ |
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41 uint16_t offset_plus1 :3; |
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42 uint16_t shift :3; ///< number of least significant bits that must be shifted away to get the value |
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43 uint16_t depth_minus1 :4; ///< number of bits in the component minus 1 |
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44 }AVComponentDescriptor; |
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45 |
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46 /** |
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47 * Descriptor that unambiguously describes how the bits of a pixel are |
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48 * stored in the up to 4 data planes of an image. It also stores the |
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49 * subsampling factors and number of components. |
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50 * |
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51 * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV |
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52 * and all the YUV variants) AVPixFmtDescriptor just stores how values |
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53 * are stored not what these values represent. |
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54 */ |
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55 typedef struct AVPixFmtDescriptor{ |
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56 const char *name; |
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57 uint8_t nb_components; ///< The number of components each pixel has, (1-4) |
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58 |
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59 /** |
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60 * Amount to shift the luma width right to find the chroma width. |
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61 * For YV12 this is 1 for example. |
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62 * chroma_width = -((-luma_width) >> log2_chroma_w) |
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63 * The note above is needed to ensure rounding up. |
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64 * This value only refers to the chroma components. |
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65 */ |
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66 uint8_t log2_chroma_w; ///< chroma_width = -((-luma_width )>>log2_chroma_w) |
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67 |
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68 /** |
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69 * Amount to shift the luma height right to find the chroma height. |
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70 * For YV12 this is 1 for example. |
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71 * chroma_height= -((-luma_height) >> log2_chroma_h) |
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72 * The note above is needed to ensure rounding up. |
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73 * This value only refers to the chroma components. |
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74 */ |
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75 uint8_t log2_chroma_h; |
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76 uint8_t flags; |
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77 |
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78 /** |
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79 * Parameters that describe how pixels are packed. If the format |
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80 * has chroma components, they must be stored in comp[1] and |
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81 * comp[2]. |
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82 */ |
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83 AVComponentDescriptor comp[4]; |
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84 }AVPixFmtDescriptor; |
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85 |
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86 #define PIX_FMT_BE 1 ///< Pixel format is big-endian. |
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87 #define PIX_FMT_PAL 2 ///< Pixel format has a palette in data[1], values are indexes in this palette. |
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88 #define PIX_FMT_BITSTREAM 4 ///< All values of a component are bit-wise packed end to end. |
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89 #define PIX_FMT_HWACCEL 8 ///< Pixel format is an HW accelerated format. |
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90 #define PIX_FMT_PLANAR 16 ///< At least one pixel component is not in the first data plane |
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91 #define PIX_FMT_RGB 32 ///< The pixel format contains RGB-like data (as opposed to YUV/grayscale) |
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92 /** |
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93 * The pixel format is "pseudo-paletted". This means that Libav treats it as |
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94 * paletted internally, but the palette is generated by the decoder and is not |
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95 * stored in the file. |
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96 */ |
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97 #define PIX_FMT_PSEUDOPAL 64 |
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98 |
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99 #if FF_API_PIX_FMT_DESC |
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100 /** |
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101 * The array of all the pixel format descriptors. |
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102 */ |
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103 extern const AVPixFmtDescriptor av_pix_fmt_descriptors[]; |
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104 #endif |
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105 |
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106 /** |
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107 * Read a line from an image, and write the values of the |
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108 * pixel format component c to dst. |
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109 * |
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110 * @param data the array containing the pointers to the planes of the image |
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111 * @param linesize the array containing the linesizes of the image |
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112 * @param desc the pixel format descriptor for the image |
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113 * @param x the horizontal coordinate of the first pixel to read |
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114 * @param y the vertical coordinate of the first pixel to read |
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115 * @param w the width of the line to read, that is the number of |
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116 * values to write to dst |
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117 * @param read_pal_component if not zero and the format is a paletted |
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118 * format writes the values corresponding to the palette |
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119 * component c in data[1] to dst, rather than the palette indexes in |
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120 * data[0]. The behavior is undefined if the format is not paletted. |
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121 */ |
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122 void av_read_image_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4], |
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123 const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component); |
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124 |
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125 /** |
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126 * Write the values from src to the pixel format component c of an |
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127 * image line. |
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128 * |
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129 * @param src array containing the values to write |
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130 * @param data the array containing the pointers to the planes of the |
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131 * image to write into. It is supposed to be zeroed. |
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132 * @param linesize the array containing the linesizes of the image |
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133 * @param desc the pixel format descriptor for the image |
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134 * @param x the horizontal coordinate of the first pixel to write |
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135 * @param y the vertical coordinate of the first pixel to write |
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136 * @param w the width of the line to write, that is the number of |
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137 * values to write to the image line |
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138 */ |
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139 void av_write_image_line(const uint16_t *src, uint8_t *data[4], const int linesize[4], |
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140 const AVPixFmtDescriptor *desc, int x, int y, int c, int w); |
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141 |
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142 /** |
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143 * Return the pixel format corresponding to name. |
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144 * |
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145 * If there is no pixel format with name name, then looks for a |
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146 * pixel format with the name corresponding to the native endian |
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147 * format of name. |
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148 * For example in a little-endian system, first looks for "gray16", |
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149 * then for "gray16le". |
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150 * |
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151 * Finally if no pixel format has been found, returns PIX_FMT_NONE. |
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152 */ |
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153 enum AVPixelFormat av_get_pix_fmt(const char *name); |
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154 |
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155 /** |
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156 * Return the short name for a pixel format, NULL in case pix_fmt is |
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157 * unknown. |
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158 * |
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159 * @see av_get_pix_fmt(), av_get_pix_fmt_string() |
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160 */ |
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161 const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt); |
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162 |
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163 /** |
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164 * Print in buf the string corresponding to the pixel format with |
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165 * number pix_fmt, or an header if pix_fmt is negative. |
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166 * |
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167 * @param buf the buffer where to write the string |
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168 * @param buf_size the size of buf |
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169 * @param pix_fmt the number of the pixel format to print the |
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170 * corresponding info string, or a negative value to print the |
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171 * corresponding header. |
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172 */ |
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173 char *av_get_pix_fmt_string (char *buf, int buf_size, enum AVPixelFormat pix_fmt); |
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174 |
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175 /** |
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176 * Return the number of bits per pixel used by the pixel format |
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177 * described by pixdesc. |
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178 * |
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179 * The returned number of bits refers to the number of bits actually |
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180 * used for storing the pixel information, that is padding bits are |
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181 * not counted. |
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182 */ |
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183 int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc); |
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184 |
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185 /** |
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186 * @return a pixel format descriptor for provided pixel format or NULL if |
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187 * this pixel format is unknown. |
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188 */ |
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189 const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt); |
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190 |
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191 /** |
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192 * Iterate over all pixel format descriptors known to libavutil. |
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193 * |
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194 * @param prev previous descriptor. NULL to get the first descriptor. |
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195 * |
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196 * @return next descriptor or NULL after the last descriptor |
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197 */ |
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198 const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev); |
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199 |
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200 /** |
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201 * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc |
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202 * is not a valid pointer to a pixel format descriptor. |
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203 */ |
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204 enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc); |
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205 |
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206 #endif /* AVUTIL_PIXDESC_H */ |
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